Centipede polymers and preparation and application in rubber compositions

ABSTRACT

The instant invention relates to poly(maleimide-co-alkenyl benzene) centipede polymer and a method for producing the polymer by reacting a poly(alkenyl benzene-co-maleic anhydride) in the presence of a primary amine in a substantially dry state. The invention is further directed to a process for blending the poly(maleimide-co-alkenyl benzene) centipede polymer with elastomeric polymers, in combination with, or in substitution of, conventional extender oils, to produce extended polymers having improved properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like.

BACKGROUND OF THE INVENTION

[0001] The polymerization of styrene and maleic anhydride by freeradical initiation is well known in the prior art. Similarly,poly(styrene-co-maleic anhydride) and poly(styrene-alt-maleic anhydride)polymers are well known. Further, imidization between a maleic anhydrideand a primary amine group is a commonly known chemical reaction.Publications which have recognized these reactions include: GermanPatent DE 4241538, assigned to Leuna-Werke A. -G; Japanese Patent JP94248017, assigned to Monsanto Kasel Kk.; and, Italian Patent EP 322905A2, assigned to Montedipe S.p.A. Various other non-patent publicationshave also recognized these reactions, Included among them are: L. E.Colleman, Jr., J. F. Bork, and H. Donn, Jr., J. Org. Chem., 24,185(1959); A. Matsumoto, Y. Oki, and T. Otsu, Polymer J.,23(3),201(1991); L. Haeussler, U. Wienhold, V. Albricht, and S.Zschoche, Themochim. Acta, 277, 14(1966); W. Kim, and K. Seo, Macromol.Rapid Commun., 17, 835(1996); W. Lee, and G. Hwong, J. Appl. Polym.Sci., 59, 599(1996); and, I. Vermeesch and G. Groeninckx, J. Appl.Polym. Sci., 53, 1356(1994).

[0002] The synthesis of monofunctional N-alkyl and N-aryl maleimides arealso well known in the prior art. They have been extensively used toimprove the heat stability of homopolymers and especially copolymersprepared from vinyl monomers. Typically, the bulk resins comprise ABS(poly-(acrylonitrile-co-butadiene-co-styrene)) or a polyblend ofpoly-(acrylonitrile-co-butadiene) and poly-(styrene-co-acrylonitrile);PVC (poly(vinyl chloride)); SAN (poly(styrene-co-acrylonitrile)); PMMA(poly-(methyl methacrylate)); and the like. The maleimides can becopolymerized with other monomers such as acrylonitrile, butadiene,styrene, methyl methacrylate, vinyl chloride, vinyl acetate and manyother comonomers. A more preferred practice in the industry is toproduce copolymers of maleimides with other monomers such as styrene andoptionally acrylonitrile and to blend these with ABS and SAN resins. Inany event, the polymer compositions are adjusted so that the copolymersare fully compatible with the bulk resins (e.g., ABS and/or SAN) asshown by the presence of a single glass transition point (T_(g)) asdetermined by differential scanning calorimetry (DSC).

[0003] It has long been recognized that two or more polymers may beblended together to form a wide variety of random or structuredmorphologies to obtain products that potentially offer desirablecombinations of characteristics. However, it may be difficult or evenimpossible in practice to achieve many potential combinations throughsimple blending because of some inherent and fundamental problem.Frequently, the two polymers are thermodynamically immiscible, whichprecludes generating a truly homogeneous product. This immiscibility maynot be a problem per se since often it is desirable to have a two-phasestructure. However, the situation at the interface between these twophases very often does lead to problems. The typical case is one of highinterfacial tension and poor adhesion between the two phases. Thisinterfacial tension contributes, along with high viscosities, to theinherent difficulty of imparting the desired degree of dispersion torandom mixtures and to their subsequent lack of stability, giving riseto gross separation or stratification during later processing or use.Poor adhesion leads, in part, to the very weak and brittle mechanicalbehavior often observed in dispersed blends and may render some highlystructured morphologies impossible.

[0004] The abrasion resistance of rubbers generally increases withincreasing molecular weight. However, viscosity of the unvulcanizedrubber also increases with increase in molecular weight. Accordingly, inconventional practice a plasticizer (“extending oil”) is added to theunvulcanized rubber to lower its viscosity and to increase itsworkability to a point suitable for extrusion or other processing.

[0005] Kent et al in U.S. Pat. No. 3,528,936 and Cowperthwaite et al inU.S. Pat. No. 3,751,378 recognize that high molecular weight polymers ofbutadiene, etc., may be plasticized by addition of certain polyestermonomers. Both patents teach admixture of the monomer and polymertogether with an inorganic filler and other ingredients on an open millor in an internal mixer, i.e., “dry” blending with a filler.

[0006] It is particularly desirable to prepare a polymer useful as anoil substitute that performs the function of a polymer extender orplasticizer while enhancing beneficial polymer properties such astensile strength, maximum elongation, tear strength, damping properties.

OBJECTS OF THE INVENTION

[0007] It is an object of this invention to produce apoly(maleimide-co-alkenyl benzene) “centipede” polymer formed byimidizing a poly(alkenyl benzene-co-maleic anhydride). The “centipede”polymer has a high molecular weight spine connected with many relativelyshort side chains. The length of the main chain usually equals or islonger than the entanglement length, which is herein definedtheoretically as an order of magnitude of 100 repeating units, while thelength of the side chains is much smaller than the entanglement length.

[0008] Still more specifically, it is an object of the invention toprovide a centipede polymer formed by imidizing a poly(styrene-co-maleicanhydride) with a primary amine to form a poly(maleimide-co-styrene)polymer.

[0009] It is a further object of the present invention to produce a highmolecular weight poly(maleimide-co-alkenyl benzene) polymer formed bythe reaction product of a maleic anhydride contributed monomer unit of apoly(alkyl benzene-co-maleic anhydride) and a primary amine containingfrom 1 to 50 carbon atoms in the alkyl and alkoxy substituents in theprimary amine.

[0010] It is another object of the invention is to produce a highmolecular weight poly(maleimide-co-alkenyl benzene) polymer useful as anoil substitute to be used as an a polymer extender that enhancesbeneficial polymer properties such as tensile strength, maximumelongation, tear strength, damping properties, and the like.

[0011] Finally, it is yet another object of the invention is to producea centipede polymer that exhibits improved properties such as tensilestrength, maximum elongation, tear strength, damping properties, and thelike; that can be employed as a substitute for oils and/or plasticizersin the production of various other rubber compounds.

SUMMARY OF THE INVENTION

[0012] The present invention is broadly directed topoly(maleimide-co-alkenyl benzene) centipede polymer compositions formedby reacting a poly(alkenyl benzeneco-maleic anhydride) with a primaryamine. It is further directed to a process for blending thepoly(maleimide-co-alkenyl benzene) centipede polymer with elastomericpolymers, in combination with, or in substitution of, conventionalextender oils, to produce extended polymers having improved propertiessuch as tensile strength, maximum elongation, tear strength, dampingproperties, and the like.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention is broadly directed to a polymercompositions of a poly(alkenyl benzene-co-maleimide) formed by reactinga poly(alkyl benzene-co-maleic anhydride) with a primary amine.

[0014] For the purposes of this invention, poly(alkenylbenzene-co-maleimide) and poly(alkyl benzene-co-maleic anhydride) aredefined to encompass random and stereo-specific copolymers, includingcopolymers having alternating alkenyl benzene and maleimide or maleicanhydride contributed monomer units along the polymer backbone. Suchalternating structure are typically described as poly(alkenylbenzene-adj-maleimide) and poly(alkyl benzene-adj-maleic anhydride),however, these polymers are encompassed herein within the descriptionspoly(alkenyl benzene-co-maleimide) and poly(alkyl benzene-co-maleicanhydride)

[0015] Processes for forming poly(alkyl benzene-co-maleic anhydride)polymers are well known to those skilled in the art. The preparation ofthe copolymers from electron donor monomers, such as styrene, andelectron acceptor monomers, such as maleic anhydride, as a result ofcomplexation of the electron acceptor monomers may be carried out in theabsence as well as in the presence of an organic free radical initiatorin bulk, or in an inert hydrocarbon or halogenated hydrocarbon solventsuch as benzene, toluene, hexane, carbon tetrachloride, chloroform, etc.(N. G. Gaylord and H. Antropiusova, Journal of Polymer Science, Part B,7, 145 (1969) and Macromolecules, 2, 442 (1969); A. Takahashi and N. G.Gaylord, Journal of Macromolecular Science (Chemistry), A4, 127 (1970).

[0016] Poly(alkyl benzene-co-maleic anhydride) polymers are prepared byreacting monomers of alkenylbenzene with maleic anhydride. The preferredalkenyl benzene monomers used for forming the poly(alkylbenzene-co-maleic anhydride) polymer are styrene or α-methylstyrene.Suitable, but less preferred substitutes are: p-methylstyrene,4-phenylstyrene, m-methylstyrene, o-methylstyrene, p-tert-butylstyrene,dimethylstyrene, and combinations thereof.

[0017] The poly(alkyl benzene-co-maleic anhydride) for use in thepresent invention is a polymer containing from about 5 to 99 molepercent of maleic anhydride monomer with the remainder being alkylbenzene monomer. The preferred poly(alkyl benzene-co-maleic anhydride)contains from 20 to 50 mole percent of maleic anhydride monomer. Themost preferred poly(alkyl benzene-co-maleic anhydride) for use in thepresent invention is poly(styrene-co-maleic anhydride) containing 50mole percent of maleic anhydride monomer and 50 mole percent of styrenemonomer. The comonomers, maleic anhydride and alkenyl benzene, can berandomly or alternatingly distributed in the chain, however, it ispreferred to have these comonomers alternating along the polymerbackbone chain.

[0018] The poly(alkenyl benzene-co-maleic anhydride) has a molecularweight range between about 1,000 and up to about 500,000 or higher, moretypically between about 10,000 and 500,000, and even more typicallybetween about 150,000 and 450,000, where the molecular weight isweight-average (“M_(w)”).

[0019] The poly(maleimide-co-alkenyl benzene) of the instant inventionis formed by reacting a poly(alkyl benzene-co-maleic anhydride) in thepresence of a mono-primary amine at a temperature from about 100° C. toabout 300° C. and at a pressure from about slightly above vacuum toabout 20 atmospheres, under substantially dry conditions. The reactantsare preferably dry mixed in the absence of solvents in a suitable mixingapparatus such as a Brabender mixer equipped with Banbury blades. It ispreferable to purge the mixer with nitrogen prior to the charging of thereactants. The primary amine may be added in a singular charge or insequential partial charges into a reactor containing a charge ofpoly(alkyl benzene-co-maleic anhydride). Preferably the primary amine ischarged in ratio between 0.8 to 1.0 of moles of amine per monomercontributed units of maleic anhydride in the poly(alkylbenzene-co-maleic anhydride).

[0020] Suitable primary amine include but are not limited to: alkylamines; alkyl benzyl amines; alkyl phenyl amines; alkoxybenzyl amines;alkyl aminobenzoates; alkoxy aniline; and other linear primary aminescontaining from 1 to 50 carbon atoms, preferably 6 to 30 carbon atoms,in the alkyl and alkoxy substituents in these primary amines. It isunderstood that the alkyl and alkoxy substituents on the above discussedprimary amines can be linear or branched, preferably linear, andsaturated or unsaturated, preferably saturated. Exemplary, but notexclusive of such amines are: hexylamine, octylamine, dodecylamine andthe like.

[0021] The poly(maleimide-co-alkenyl benzene), preferably has amolecular weight range between about 1,000 and up to about 500,000 orhigher, more typically between about 10,000 and 500,000, and even moretypically between about 150,000 and 450,000, where the molecular weightis weight-average (“M_(w)”).

[0022] The poly(maleimide-co-alkenyl benzene) centipede polymers of thepresent invention can be employed as high damping additives and as analternative for plasticizers or oils in the formulation of variousrubber compounds or elastomeric polymers.

[0023] The centipede polymer of the present invention may be prepared byany means well known in the art for combining such ingredients, such asblending, milling or internal batch mixing. A rapid and convenientmethod of preparation comprises heating a mixture of the components to atemperature of about 50° C. to about 290° C.

[0024] The centipede polymers of this invention are preferablymanufactured by mixing and dynamically heat-treating the componentsdescribed above, namely, by melt-mixing. As for the mixing equipment,any conventional, generally known equipment such as an open-type mixingroll, closed-type Banbury mixer, closed type Brabender mixer, extrudingmachine, kneader, continuous mixer, etc., is acceptable. The closed-typeBrabender mixer is preferable, and mixing in an inactive gasenvironment, such as nitrogen or carbon dioxide, is also preferable.

[0025] In accordance with the present invention, the centipede polymercomposition of the present invention may be added as an extender or as aplasticizer to an elastomeric polymer in an amount ranging from about0.5-200 parts by weight per 100 parts by weight of a solid elastomericpolymer; preferably in an amount ranging from about 0.1 to about 50parts by weight of centipede polymer per 100 parts by weight of theelastomeric polymer to be extended. Most preferred amounts of addedcentipede polymer include from about 0.5 to about 20 parts of centipedepolymer per 100 parts of the elastomeric polymer. These parts by weightbeing effective plasticizing amounts of centipede polymer in elastomers.

[0026] Typical, but by no means limited to the types ofthermodynamically miscible elastomeric polymers and copolymers that maybe compatibly blended and extended by the centipede polymers of thepresent invention are elastomeric polymer containing formulationsinclude but not limited to: natural rubber, polyisoprene, polybutadiene,butadiene/styrene rubber (SBR), ethylene/propylene copolymer rubbers andblends thereof SBR and polybutadiene are preferred elastomers.

[0027] The use of poly(maleimide-co-alkenyl benzene) centipede- polymersproduced according to the present invention as plasticizers forelastomeric polymers either alone or as a partial oil substituteincreases the damping properties of the elastomeric polymers overcomparable oil extended polymers. The use of the centipede polymers asan extender in elastomeric polymers also increases the tensile strength,the maximum elongation, tear strength and the travel at tearcharacteristics versus elastomers extended with a comparable amount ofoil extender.

[0028] Although the present invention also contemplates use of theinstant centipede polymers in combination with conventional extenderoils, an embodiment contemplates the total substitution of conventionalextenders by centipede polymers. Typical prior art extenders replaced bythe instant centipede polymers include extender oils and low molecularweight compounds or components. Such extender oils include those wellknown in the art such as naphthenic, aromatic and paraffinic petroleumoils and silicone oils. Examples of low molecular weight organiccompounds or components extenders in the compositions that may bereplaced by the centipede polymers of the present invention are lowmolecular weight organic materials having a number-average molecularweight of less than 20,000, preferable less than 10,000, and mostpreferably less than 5,000. Although there is no particular limitationto the material that the instant centipede polymers replace in prior artrubber compounds, the following is a list of examples of appropriatereplaceable materials: (1) softening agents, namely aromatic, naphthenicand paraffinic oil softening agents for rubbers or resins; and (2)plasticizers, namely plasticizers composed of esters includingplithalic, mixed phthalic, aliphatic dibasic acid, glycol, fatty acid,phosphoric and stearic esters, epoxy plasticizers, other plasticizersfor plastics; and (3) petroleum hydrocarbons, namely synthetic terpeneresins, aromatic hydrocarbon resins, aliphatic hydrocarbon resins,aliphatic cyclic hydrocarbon resins, aliphatic or alicyclic petroleumresins, aliphatic or aromatic petroleum resins, polymers of unsaturatedhydrocarbons, and hydrogenated hydrocarbon resins. The instant centipedepolymers can be used to replace or partially replace one or more or allof these extender materials.

[0029] Additives useful in the compositions of the present applicationas well known in the rubber art. Stabilizers, antioxidants, conventionalfillers, reinforcing agents, reinforcing resins, pigments, fragrancesand the like are examples of some such additives. Specific examples ofuseful antioxidants and stabilizers include2-(2′-hydroxy-5′-methylphenyl) benzotriazole, nickeldibutyldithiocarbamate, zinc dibutyl dithiocarbamate, tris(nonylphenyl)phosphite, 2,6-di-t-butyl-4-methylphenol and the like. Exemplaryconventional fillers and pigments include silica, carbon black, titaniumdioxide, iron oxide and the like. These compounding ingredients areincorporated in suitable amounts depending upon the contemplated use ofthe product, preferably in the range of 1 to 350 parts of additives orcompounding ingredients per 100 parts of the elastomeric polymer.

[0030] A reinforcement may be defined as the material that is added to athe elastomeric compositions to improve the strength of the centipedeextended elastomeric polymer. Most of these reinforcing materials areinorganic or organic products of high molecular weight. Various examplesinclude glass fibers, asbestos, boron fibers, carbon and graphitefibers, whiskers, quartz and silica fibers, ceramic fibers, metalfibers, natural organic fibers, and synthetic organic fibers. Otherelastomers and resins are also useful to enhance specific propertieslike damping properties, adhesion and processability. Examples of otherelastomers and resins include adhesive-like products including Reostomer(produced by Riken-Vinyl Inc.), hydrogenated polystyrene-(medium or high3,4) polyisoprene-polystyrene block copolymers such as Hybler (producedby Kurare Inc.), polynorbornenes such as Norsorex (produced by NipponZeon Inc.) and the like.

[0031] The centipede extended elastomer compositions obtained using themanufacturing method of this invention can be molded with equipmentconventionally used for molding thermoplastics. These centipede extendedelastomer compositions are suitable for extrusion molding, calendarmolding, and particularly injection molding. These compositions can bemixed in any conventional mixer such as a Brabender mixer, a Banburymixer or roll mill or extruder normally conducted within the temperaturerange of about 100 ° C. to about 300 ° C., preferably maintaining thecomposition above its melting point for a few minutes up to severalhours, preferably 10 to 40 minutes. A particularly useful technique isto add any fillers in the beginning of the mixing cycle in order to takemaximum advantage of heating time and to prevent surface bleeding andoverheating when forming the molded articles.

[0032] The centipede extended elastomeric polymer formulations may bemolded in appropriate press ovens and the like to form products in theform of extruded pellets, cut dices, preferably as small as possiblesince smaller pellets provide short heating times and better flow whenutilized in flow molding. Ground pellets may also be utilized.

[0033] In summary, the poly(maleimide-co-alkenyl benzene) centipedeextended elastomeric polymer formulations of the instant invention canbe used in high temperature applications including uses in injectionmolding or in any other compositions typically for elastomericproperties. The use of the centipede polymers as an extender inelastomeric polymers increases the tensile strength, the maximumelongation, tear strength and the travel at tear characteristics versuselastomers extended with a comparable amount of oil extender.

[0034] Damping is the absorption of mechanical energy by a material incontact with the source of that energy. It is desirable to damp ormitigate the transmission of mechanical energy from, e.g., a motor,engine, or power source, to its surroundings. Elastomeric materials areoften used for this purpose. It is desirable that such materials behighly effective in converting this mechanical energy into heat ratherthan transmitting it to the surroundings. It is further desirable thatthis damping or conversion is effective over a wide range oftemperatures and frequencies commonly found near motors, automobiles,trucks, trains, planes, and the like.

[0035] A convenient measurement of damping is the determination of aparameter called tan δ. A forced oscillation is applied to a material atfrequency f and the transmitted force and phase shift are measured. Thephase shift angle delta is recorded. The value of tan δ is proportionalto the ratio of (energy dissipated)/(energy stored). The measurement canbe made by any of several commercial testing devices, and may be made bya sweep of frequencies at a fixed temperature, then repeating that sweepat several other temperatures, followed by the development of a mastercurve of tan δ vs. frequency by curve alignment. An alternate method isto measure tan δ at constant frequency (such as at 10 hz) over atemperature range. We have defined an unfilled material as useful fordamping when tan δ>˜0.3 over at least a 4 decade range, preferably a 6decade range of frequency.

[0036] It is further important that-this high degree of absorption ofenergy be accompanied by good mechanical and thermal stability, as thepart prepared from the subject centipede extended polymers will becycled through various environments and repeatedly such to variousforces of compression, tension, bending, and the like.

[0037] The compositions of the present invention are favorably used inthe manufacturing of any product in which the following properties areadvantageous: a high degree of softness, heat resistance, decentmechanical properties, elasticity and/or high damping. The compositionsof the present invention can be used in all industry fields, inparticular, in the fabrication of automotive parts, tire tread rubbers,household electrical appliances, industrial machinery, precisioninstruments, transport machinery, constructions, engineering, andmedical instruments.

[0038] Representative examples of the uses of the instant centipedeextend elastomeric polymers are damping materials, and vibrationrestraining materials. These uses involve connecting materials such assealing materials, packing, gaskets and grommets, supporting materials,such as mounts, holders and insulators, and cushion materials such asstoppers, cushions, and bumpers. These materials are also used inequipment producing vibration or noise and household electricalappliances, such as in air-conditioners, laundry machines,refrigerators, electric fans, vacuums, driers, printers and ventilatorfans. Further, these materials are also suitable for impact absorbingmaterials in audio equipment and electronic or electrical equipment,sporting goods and shoes.

[0039] In the following, the present invention will be described in moredetail with reference to non-limitative examples. The following examplesand tables are presented for purposes of illustration only and are notto be construed in a limiting sense.

Preparation of Centipede Polymer EXAMPLE 1

[0040] A nitrogen purged Brabender mixer (˜310 gram capacity) equippedwith a Banbury blade was initially set to 30 rpm and the temperature wasset to 165 ° C. The mixer was then charged with 150 g ofpoly(styrene-alt-maleic anhydride) (obtained from Aldrich ChemicalCompany of 1001 West Saint Paul Avenue, Milwaukee, Wis. Catalog Number:18,293-1, CAS Number: 9011-13-6)(M_(n)=350,000) and 34.5 g of dodecylamine (obtained from Aldrich, 98% purity). The contents of the mixer wasthen agitated for 10 minutes and then a charge of another 34.5 g ofdodecyl amine was added to the mixer. This procedure was repeated 3times until a total of 138 g of dodecyl amine had been added to themixer. After 30 minutes of continuous mixing, the agitation speed wasreset to 60 rpm and the temperature was reset to 205° C. Agitation wascontinued for an additional 65 minutes. Agitation was thereafter resetto 15 rpm and the heating element of the mixer was turned off, and thepolymer mass within the mixer was permitted to cool down to 150° C. at arate of ˜4° C./min. The agitation was then stopped and the centipedepolymer product mass was then removed from the mixer.

[0041] IR absorption peaks characteristic of the centipede polymer masswere noted substantially only at 704 cm⁻¹, 1701 cm⁻¹, 1772 cm⁻¹, 2852cm⁻¹ and 2923 cm⁻¹. The ratio of the intensities was observed at I₂₉₂₃to I₁₇₁₀≈0.8. Further, an NGR analysis (¹H and ¹³C) indicated that theimidization reaction within the product mass had achieved a 100%completion. It was not possible to define the T_(g) value since thecharacteristic T_(g) transition is very broad when using DSC. No stepchange in heat capacity was noted (i.e., ΔCp. vs. Temperature).

EXAMPLE 2

[0042] The same nitrogen purged Brabender mixer (˜310 g capacity)equipped with a Banbury blade of foregoing Example 1 was initially setto 30 rpm and the temperature was set to 80° C. The mixer was thencharged with 150 g of poly(styrene-alt-maleic anhydride) (obtained fromAldrich, M_(n)=350K) and 96 g of octyl amine (obtained from Aldrich, 99%purity). After 5 minutes, the mixture was permitted to heat up at a rateof 4° C./min. Once the temperature of the mixture reached 140° C., theagitation was discontinued. When the temperature of the mixture rose to250° C., the heating element of the mixer was set to isothermal mode andthe agitation was resumed at a speed of 30 rpm. After 5 minutes ofcontinuous mixing, the agitation speed was reset to 70 rpm and thetemperature was reset to 210° C. Agitation was continued for anadditional 65 minutes. The heating element of the mixer was then turnedoff, and the polymer mass within the mixer was permitted to cool down ata rate of ˜4° C./min. The agitation was then turned off and thecentipede polymer product mass, while at temperature of 160° C., wasthen removed from the mixer.

[0043] IR absorption peaks characteristic of the centipede polymer masswere noted substantially only at 705 cm⁻¹, 1701 cm⁻¹, 1770 cm⁻¹, 2855cm⁻¹ and 2926 cm⁻¹. The ratio of the intensities was observed at I₂₉₂₆to I₁₇₀₁≈0.55. Further, an NGR analysis (¹H and ¹³C) indicated that theimidization reaction within the product mass had achieved a 100%completion (i.e., no traces of maleic anhydride peaks at 1770 cm⁻¹ and1855 cm⁻¹; and, amino group peaks at 3330 cm⁻¹). Although the DSCcharacteristic T_(g) transition was very broad, between −50° C. to 75°C., the T_(g) was estimated at 60° C.

EXAMPLES 3-9 Application of Centipede Polymers in Rubber Compounds

[0044] In Examples 3 to 9, rubber compositions were prepared accordingto the formulation as displayed in parts by weight as shown in Table 1.In Examples 4 to 8 the centipede polymer of Example 1 was used to atleast partially replace that amount of aromatic oil normally used, asshown in Table 3. Although the respective amounts of aromatic oil andcentipede polymer were varied, the sum of the respective amounts (18.25parts by weight) was kept constant in all compounds. The rubber compoundused in the formulation in Table 1 was an oil-extended high-styrene SBR(20 phr aromatic oil) which contained 33% bound styrene with aT_(g)=−47° C. The cis-BR used was a high-cis polybutadiene with a ciscontent=96%. In each sample, the components were kneaded by the methodindicated in Table 2. The final stock was sheeted and molded at 165° C.for ˜15 minutes. For each of the sample vulcanized rubber compounds ofExamples 3 to 9, measurements of the tensile strength; tear strength;and, hysteresis loss were taken. The results of these measurementsappears in Table 3. Measurements of tensile strength were based upon theconditions of ASTM-D 412 at 22° C. Test specimen geometry was taken inthe form of a ring having a width of 0.05 inches and a thickness of0.075 inches. The specimen was tested at a specific gauge length of 1.0inches. The measurement of tear strength is based on conditions ofASTM-D 624 at 170° C. Test specimen geometry was also taken in the formof a nicked ring in accordance with the conditions defined inASTM-624-C. The specimen was tested at the specific gauge length of1.750 inches. The hysteresis loss was measured with a DynastatVicoelastic Analyzer. The test specimen geometry was also taken in theform of a cylinder of a length of 0.6125 inches and a diameter of 0.375inches. The specimen was tested at a frequency of 1 Hz and a temperatureof 50° C. A static mass of 2.0 Mpa and a dynamic mass of 2.50 MPa wereapplied for the test. As can be seen in Table 3, the rubber compositionsof Examples 4-8 exhibited very well balanced: tensile strengths; tearstrengths; and, damping properties. An evaluation of the resistance ofthe samples was obtained by weighing the amount of wear. Assuming allconsiderations were based upon the same modulus condition, nosignificant differences were observed between the test samples and thecomparative samples.

[0045] Accordingly, it was concluded that the polymers developedaccording to the instant invention (as shown in samples 1-2) aresuitable as high damping additives in rubber compounds. It was furtherconcluded that these polymers could be used as alternative substitutesfor oils and/or plasticizers. TABLE 1 Styrene-Butadiene Rubber 96.80(SBR, Duradene 753) Butadiene Rubber (cis-BR, Diene 600) 20.00 CarbonBlack (ISAF) 70.00 Aromatic Oil 18.25 Stearic Acid 2.00 Wax 1.50Antioxidant [N-(1,3 dimethybutyl)- 0.95 N′-phenyl-p-phenylene-diamine]Sulfur 1.70 Accelerator [N-tert-butyl- 0.80 benzothiazolesulfenamine]Zinc Oxide 2.00 Antioxidant [polymerized 1,2-dihydro- 0.222,2,4-trimethylquioline] Accelerator (benzothiazyl disulfide) 0.20Accelerator (tetra-methylthiuram monosulfide) 0.20

[0046] TABLE 2 Mixer 310 g Brabender Agitation Speed  60 rpm Mater BatchStage Initial Temperature 110° C.  0 sec charging polymers 30 seccharging carbon black and all pigments  5 min drop Remill Batch StageInitial Temperature 110° C.  0 sec charging mater batch stock  4 mindrop Final Batch Stage Initial Temperature  75° C.  0 sec chargingremilled stock 30 sec charging curing agent and accelerators 80 sec drop

[0047] TABLE 3 Polymer Sulfur used: Ex 1 used Tensile Maximum TearExample (parts by (parts by strength elongation strength Travel at Tan δNo. weight) weight) (psi) (%) (psi) Tear (%) at 50° C. 3 (comp.) 0 1.72928 564 209.4 326.4 0.245 4 5 1.7 3264 598 290.0 409.1 0.255 5 10 1.72876 564 304.8 423.2 0.274 6 15 1.7 2916 549 325.6 431.8 0.308 7 8 1.73212 573 294.5 403.6 0.253 8 12 1.7 3147 605 311.7 426.9 0.293 9 (comp.)0 2.0 3166 535 237.8 315.4 0.221

[0048] Table 3 shows a series of seven examples wherein a dampingpolymer that was extended only by conventional extender oils incomparative Examples 3 (comp) and 9 (comp)), was compared to the samedamping polymer extended with varying proportions of the instantcentipede polymer to conventional extender oils while maintaining aconstant total extender oil weight proportion of 18.25 parts by weightof extender. For example, Example 3 contained 18.25 parts by weight ofaromatic oil while Example 4 contained 13.25 parts by weight of aromaticoil and 5 parts by weight of centipede polymer as prepared in Example 1.Substantial improvements can be noted in the examples that werepartially extended with the centipede polymer of the present invention,with respect to tensile strength, tear strength, travel at tear and tanδ at 50° C.

[0049] Although the invention has been described with reference toparticular means, materials and embodiments it is to be understood thatthe invention is not limited to the particulars disclosed and extends toall equivalents within the scope of the claims.

We claim:
 1. A polymer composition, comprising apoly(maleimide-co-alkenyl benzene).
 2. The polymer composition of claim1, wherein the alkenyl benzene moiety of said poly(maleimide-co-alkenylbenzene) is selected from the group consisting of: styrene,α-methylstyrene, tert-butylstyrene, p-methylstyrene, 4-phenylstyrene,3-methylstyrene, m-methylstyrene, o-methylstyrene, dimethylstyrene, andcombinations thereof
 3. The polymer composition of claim 1, wherein themaleimide moiety of said poly(maleimide-co-alkenyl benzene) is thereaction product of a maleic anhydride contributed monomer unit of apoly(alkyl benzene-co-maleic anhydride) and a primary amine.
 4. Thepolymer composition of claim 3, wherein the primary amine is selectedfrom the group consisting of: alkyl amines; alkyl benzyl amines; alkylphenyl amines; alkoxybenzyl amines; alkyl aminobenzoates; and alkoxyaniline; containing from 1 to 50 carbon atoms in the alkyl and alkoxysubstituents in the primary amine.
 5. The polymer composition of claim3, wherein the primary amine contains alkyl or alkoxy substituentscontaining from 6 to 30 carbon atoms in the alkyl and alkoxysubstituents.
 6. The polymer composition of claim 3, wherein thepoly(alkyl benzene-co-maleic anhydride) comprises from about 5 to 99mole percent of maleic anhydride monomer.
 7. The polymer composition ofclaim 3, wherein the poly(alkyl benzene-co-maleic anhydride) comprisesfrom 20 to 50 mole percent of maleic anhydride monomer.
 8. The polymercomposition of claim 3, wherein the poly(alkyl benzene-co-maleicanhydride) comprises 50 mole percent of maleic anhydride monomer and 50mole percent of styrene monomer.
 9. The polymer composition of claim 3,wherein the poly(alkyl benzene-co-maleic anhydride) comprisesalternating maleic anhydride and alkenyl benzene contributed monomerunits.
 10. The polymer composition of claim 1, wherein saidpoly(maleimide-co-alkenyl benzene) has a molecular weight range betweenabout 1,000 and up to about 500,000.
 11. The polymer composition ofclaim 1, wherein the alkenyl benzene moiety of saidpoly(maleimide-co-alkenyl benzene) is styrene.
 12. The polymercomposition of claim 1, wherein the poly(maleimide-co-alkenyl benzene)is poly(maleimide-co-styrene).
 13. A method for the formation of apoly(maleimide-co-alkenyl benzene) polymer, comprising: reacting apoly(alkenyl benzene-co-maleic anhydride) in the presence of a primaryamine in a substantially dry state and in respective weight proportionssufficient to form a poly(maleimide-co-alkenyl benzene) polymer.
 14. Themethod of claim 13, wherein the monomer for forming the alkenyl benzenemoiety of said poly(maleimide-co-alkenyl benzene) is selected from thegroup consisting of: styrene, α-methylstyrene, tert-butylstyrene,p-methylstyrene, 4-phenylstyrene, 3-methylstyrene, m-methylstyrene,o-methylstyrene, dimethylstyrene, and combinations thereof.
 15. Themethod of claim 13, wherein said primary amine is selected from thegroup consisting of: alkyl amines; alkyl benzyl amines; alkyl phenylamines; alkoxybenzyl amines; alkyl aminobenzoates; and alkoxy aniline;containing from 1 to 50 carbon atoms in the alkyl and alkoxysubstituents in the primary amine.
 16. The method of claim 13, whereinsaid formation is conducted at temperatures from about 100° C. to about300° C.
 17. A plasticized elastomer composition comprising 100 parts byweight of a solid elastomeric polymer; and 0.5-200 parts by weight of apoly(maleimide-co-alkenyl benzene).
 18. The plasticized elastomer ofclaim 17, wherein comprising from about 0.1 to about 50 parts by weightof poly(maleimide-co-alkenyl benzene) per 100 parts by weight of theelastomeric polymer.
 19. The plasticized elastomer of claim 17, whereinthe elastomeric polymer is selected from the group consisting of:natural rubber, polyisoprene, polybutadiene, styrene/butadiene rubber(SBR), and ethylene/propylene copolymer rubbers.
 20. The plasticizedelastomer of claim 17, wherein the monomer for forming the alkenylbenzene of said poly(maleimide-co-alkenyl benzene) is selected from thegroup consisting of: styrene, α-methylstyrene, tert-butylstyrene,p-methylstyrene, 4-phenylstyrene, m-methylstyrene, o-methylstyrene,dimethylstyrene, and combinations thereof.
 21. The plasticized elastomerof claim 17, having damping properties having a tan δ in the range ofabout 1 to about 0.10 over the temperature range of 30° C. to 100° C.22. The plasticized elastomer of claim 17, further comprising from 1 to350 parts of a inorganic filler, additive or compounding ingredientbased on 100 parts by weight of the solid elastomeric polymer.
 23. Theplasticized elastomer of claim 17, wherein the extender is at least onecompound selected from the group consisting of: softening agents,plasticizers, tackifiers, oligomers, lubricants, petroleum hydrocarbons,silicone oil, aromatic oil, naphthenic oil and paraffinic oil.
 24. Amethod for producing a vulcanizable elastomeric composition comprising:providing 100 parts by weight of a solid elastomeric polymer; adding toand admixing with said elastomeric polymer 0.5-200 parts by weight of apoly(maleimide-co-alkenyl benzene).